Diesel Generator (DG) Flashcards
What is the continuous rated KW output for Diesel generator ?
5500kw
What is the intermittent output ?
6050KW (2hr in a 24hr period)
What is the continuous rated HP output ?
7670HP
What does the DG system respond automatically to ? What does diesel generator automatically start on ?
ESFAS signal:
-Safety Injection Actuation Signal(SIAS)
-Auxiliary Feed water Actuation Signal(AFAS)
-Loss Of Power(LOP)
-Containment spray actuation signal(CSAS)
What’re the 3 modes on the selector switch ?
OFF/LOCAL/REMOTE
What is the OFF position used for ?
-Used during maintenance to inhibit automatic,local,and remote starts.
-send alarm to Local control room and Main control room
What is the Local position used for ?
-Able to manual start diesel generator
-Diesel generator will be able to start on an emergency signal
-NO remote start
What is remote start used for on selector switch?
-Can be started from Main Control room or from emergency signal
-Local manual start control panel disabled
What’re the Manual Start & Stop push buttons?
-Manual start will start DG in test mode
-Manual Stop will stop DG only if in test mode
What do the Emergency start push buttons do ?
Will start DG in emergency mode:
-Simulated LOP
-Simulated ESF actuation
What’re the Emergency Stop and Reset push buttons for ?
-Emerg. Stop button will open DG output breaker and stop it without 5 minute cooldown (Will Alarm)
-Reset button clears the stop signal to allow DG to be restarted
What’re the First Out and System reset buttons used for ?
-Reset all cleared alarms on the local DG control panel
-Verify with control room no active signals are active that’ll auto start Emerg. Mode when pressed
-First Out system provides indication, by different alarm flash sequence, of first trip signal that caused DG trip
What is the Emergency Mode interlock defeat switch for ?
Key locked control mode selector:
-OFF position allows DG to start and run in Emerg. Mode. This is normal position
-ON position returns DG to test mode from Emerg run conditions
How will the DG start on a LOP signal ?
The affected Train DG will automatically start & output breaker will auto close if conditions are met
What conditions will a LOP of power be initiated on PB bus ?
Degraded voltage- 90%(30seconds)
Under voltage- 75%(instantly)
How will the DG start on a SIAS signal ?
-Both DGS will start in Emerg. Mode in a no load standby position.
-DG output breakers stay open and must be manually closed
How will the DG start up on a Auxiliary Feed Water Actuation (AFAS)signal ?
-Both DG start up in Emerg. Mode no load, standby position
- Output breaker stay open, until manually closed
How will DG startup on a Containment Spray Actuation Signal (CSAS)?
-Both DG start in Test Mode in no load ,standby position
-Output breakers remain open and must be manually closed
How’re SIAS & CSAS signals generated ?
Generated from Containment pressure rising:
SIAS-3 psig
CSAS-8 psig
How will the DG operate while in Emergency mode ?
-Will operate in isochronous mode with frequency at 60HZ
-Emerg. Mode light will be lit on local control panel
How will DG operate if started in Test Mode?
-Will operate in droop mode,speed and voltage will be in predetermined position of DG speed and voltage adjustment potentiometer setting
How do you check what Run Mode the DG is in ?
By looking at local control panel and seeing the Emerg. Mode Light
What conditions need to be met for ESFAS load sequencer, to auto close output breaker ?
-DG at rated speed:600rpm
-DG at rated voltage: 4.16kv
-No faults on PB buses Normal or Alt. Breaker (86 lockout)
-Both Norm. & Alt. breakers for respective Train Class bus are open
-LOP signal
What’re necessary conditions for the DG output breaker to be closed locally ?
DG output breaker should only be closed on a dead bus when DG output breaker is being closed locally
What is the DG Starting Air Subsystem for ?
-Provides storage and control of compressed air to start the Diesel Generator
How does air start the Diesel Generator?
Provides pressurized air to the top of the pistons, which turns the crankshaft
What Non-Safety/Safety related components does the Starting Air System have ?
Non-Safety:
-Two redundant air compressors
-Two redundant coalescing filters and air dryers
Safety related: (PER TRAIN)
-Two air receivers
-Two engine starting air control valves
-Two air distributors
-Twenty starting air valves(on cylinder head)
Where do the compressors draw air from and how is moisture removed from compressed air before being stored?
-Draws from ambient air through Intake Air Filters
-Air dryers remove moisture before going into Air Receivers
What is the Air receiver constantly aligned with ?
The Starting Air Control Valves
Where does the small air line that is tapped off just before the Starting Air Control Valves send air to ?
-Control air filters
-Mechanical turning gear interlock control valves
-Starting air solenoid valves
-Shuttle valve that opens starting air control valves
What is the second flow path of the small air line coming just before Starting Air Control Valves ?
-Through shuttle valve
-Control Air Filter
-Control Air Network
What is the air regulated for Control Air Network ?
-80psig for Emerg. Run trips and control cylinder
-37psig for operation of Test Run Trip Header and temperature control for intercooler heater core
When will the Air Solenoid Valves open and provide air through the shuttle valve to the starting air control valve ?
On a automatic start / manual start of diesel generator
What happens when the engine reaches 280RPM ?
The Starting Solenoid Valves will de-energize and will depressurize, and diesel engine will take over
What is the air pressure that starts the Diesel Generator at ?
250psig
What powers the air compressor motors ? What is the relief valve discharge pressure set point?
-NH system powers 15HP motor
-265psig will open relief valve protecting the system
When will the air compressor START/STOP? What kind of switch does the air compressor have ?
- Will receive a start signal when Air Receiver reaches 240 psig
-Will stop when Air Receiver reaches 250 psig again
-Compressor has Auto/Stop and Start, which is normally in Auto/Stop
What is used to keep the oil warm and moisture free inside the air compressor?
-There is an immersion heater with a Temp. Switch
-If oil temp. to low it’ll kick on heater
How are you supposed to check oil level on air compressor ?
-Glass gauge isolation valve must be open to check oil level
-Must also be closed when in operation
What’re Intercooler & Aftercoolers for ?
Intercooler cools the air between 1st & 2nd stages, and between 2nd & 3rd stages of the compressor
Aftercooler cools the air discharging from 3rd stage going to the air dryers
How does the compressor provide cooling to the intercoolers and after coolers ?
It uses the belt-wheel fan ON the compressor to blow air across intercooler fins
What is done to prevent condensate build up in compressor ?
Condensate is drained from 2nd stage intercooler & aftercooler
What’re the air dryers comprised of ?
Precoolers/preheaters,separators, and typical chiller package
How does air dryer chiller package work ?
Uses refrigerant to lower temp and dew point of compressed air, which separates moisture from the compressed air.
Where do the Air dryers receive their power from ?
NH system
How many Diesel Starts from a full 250psig charged Air Receiver?
You can get 5 Diesel starts from a full Air Receiver
Where can Air receiver pressure be monitored at ?
Locally on the Air receiver & on the DG control panel
When will an Air Receiver common alarm come in on the local DG control panel ?
-If the isolation valve on outlet of receiver is closed
-If Air Receiver pressure falls below 185psig and isn’t restored above 185 psig after 3 minutes
What’re the two outlet flow paths for the Starting Air Control Valves ?
-Outlet from main valve goes to Starting Air Header (Normally closed unless engine start signal is received)
-small secondary outlet provides control air
Why must Air Receiver always be applying compressed air to the Starting Air Control Valves ?
-To supply engine Control Air system
-To have the ability to automatically start
Why is there two solenoid valves ? When will will these solenoid valves open ?
-There is two just in case one fails, it won’t affect an emergency startup
-Solenoids will open on a engine start signal , which will open the Starting Air Control Valve
Why’re the Starting Air Headers cross connected?
Just in case one Starting Control Valve fails, both starting air header will still be able to receiver 250psig from the working control valve
What opens the Starting Air Valve(Cylinder Head) ?
The Starting Air Distributer pushes air(250#) down on piston, which eventually overcomes spring force and opens the Starting Air Valve, letting Starting Header Air pass into the cylinder. Which turns the crankshaft to start engine
Where is the Starting Air distributer located on the engine ?
Located at toward end of the engine, which is driven by camshaft through a splined shaft
What is the Air Distributer used for ?
It times which Starting Air Valves open and close in the correct sequences during an engine start
What prevents condensation in the Starting Air Header & any combustible leak by from cylinders?
Small amount of air is pulled off discharge of compressor and send it through Starting Air Header and is vented through Starting Air Control Valve
What pressure is sent to the turn gear assembly? What happens if a start signal is initiated while turning gear is engaged ?
-A pressure regulator reduces 250psig to 100psig, which is sent to turning gear
-There is an interlock that won’t let Starting Air Control Valves to be opened
What is the Tech Spec that is associated with Starting Air subsystem?
-Need one Air Receiver capable of delivering 230psig (allows 5 startups)
-Ensure DG is able to start in time
What do the Air Intake and Exhaust subsystem do for diesel engine ?
-Intake provides clean cool air at a high pressure for efficient combustion
-Exhaust discharges exhaust gases to atmosphere
-Has intake silencers
What is the intake flow path?
Goes through Air filter, Air intake silencer, Overspeed Butterfly Valve,& Suction of Turbocharger compressor
What is the exhaust flow path ?
-Exhaust gases leave combustion chamber and goes to exhaust manifold
-Flows hot air into the Turbocharger Turbine causing it to spin
- discharged of turbine flows exhaust to exhaust silencer and discharges to atmosphere
How do the Air intake filter work ?
Uses an oil bath to remove dust and particles from air
How does the Intake Silencer work ?
Uses baffles to reduce noise going to turbocharger
When does the Turbocharger Butterfly Valve trip ?
It trips on 660 RPM, which will shut off air supply to combustion chambers and stops the engine
How do you reset a tripped Turbocharger Butter fly Valve?
Manually reset by resetting overspeed governor and pulling butterfly handle until latches
-This is the only direct mechanical trip that’ll trip the DG on overspeed
What is the TurboCharger lubricated from? What cools the Turbocharger ?
-It’s lubricated by Engines Lube Oil system
-Cooled by Engine Jacket Water system
What is the intercooler heater used for ? Where does the intercooler get its heat from ?
It keeps the intake manifold warm so diesel can start up in 10 seconds. It keeps it warm by sending warm jacket water through intercooler
What is the large intercooler cooler on the intake flow path used for ? Where does it get its cooling water from ?
-It’s used to cool the air that was compressed by the turbocharger
-Receives its cooling from spray ponds
Where are all major components of the Fuel supply located ?
Located:
-On the engine
-Auxiliary Skid
-136ft of Diesel Building
-South of control building in vault underground
What’re the major components of Fuel Oil Storage subsystem ?
-Fuel Oil Storage Tanks
-Fuel Oil Transfer Pump
-Fuel Oil Supply Headers Strainers
-Fuel Oil Day Tanks
What’re the major components of Fuel Oil Supply subsystem? (Delivers fuel from Fuel Oil Day Tanks to high pressure fuel subsystem )
-Duplex Fuel Strainer
-Engine-Driven Booster Pump
-Duplex Fuel Filter
-Engine Head Tank
-Fuel Injection System
-Fuel Drains
What is the High Pressure Fuel subsystem for? What’re major components of the system ?
-The system provides fuel to cylinder according to main governor demand.
Components:
-Injection pump
-Fuel Injector
What is the flow path for the Diesel Fuel Oil and Transfer subsystem?
1.)Fuel Oil Transfer Pumps transfer fuel from storage tanks
2.)Through 1of2 Fuel Oil Supply header Strainers
3.)To associated train Fuel Oil Day Tank
When does Fuel Oil Transfer pump Start & Stop ?
Starts at 731 gallons and stops when it reaches full capacity in the Fuel Oil Day Tank
What’re the Cross connect lines for on the Fuel Oil Transfer system ?
So that either Transfer pump can discharge to Fuel Oil Day tank supply redundant DG.
What’re the modes that can’t have cross connections in fuel supply system ?
Normal operations:
1,2,3,4
It would violate independence and redundancy
What’re the fuel injection pumps driven by ?
They’re driven by the lobes on the camshaft and deliver specific amount of fuel based on the loading of diesel
What happens to excess fuel oil in Fuel Injection Pumps ?
It drains into Fuel Oil Return Header and back to Fuel Oil Day Tank
What is the small amount of fuel oil that travels through Fuel Injection pumps to Fuel Oil Drain Headers ?
It’s cools the Fuel Injection pumps
What is flow path from fuel oil day tank to diesel engine ? (Diesel engine running)
1.)Gravity feed from Day tank
2.)Through 1of2 suction strainers
3.)Engine driven booster pumps
4.)Discharge of booster pump goes to one side of duplex filters
5.)Then goes to Fuel Oil Supply Header & fuel oil tank on the engine
6.) Fuel is provided to right and left bank of Fuel Injection Pumps
What’re the major details about the Fuel Oil Storage Tank ?
-Buried below frost line to be protected weather,flooding, tornados,& missile hazards
-Capacity of 84000 gallons for 7day operation at 100%
-15% margin of fuel for testing
-Connections for fuel truck refill & portable pump for sampling and drawing water bottom of tank
What’re major details about Fuel Oil Transfer Pump ?
-Powered by PH system
-Submerged inside Fuel Oil Storage Tank
-Able to provide more than twice consumption rate of diesel at full power
-Pump bearings cooled pumped fuel oil
-Integral suction strainer
-In auto cycles on & off to maintain level in Fuel Day Tank
What’re the Fuel Oil Supply Header Strainers used for ?
-They’re used on discharge of transfer pump to catch debris going to Fuel Oil Day Tank
-Fast change duplex strainer changes on High DP
-Manual bypass if both both strainers are clogged
-Alarm actuates on high DP across strainer
Major details of Fuel Oil Day Tank ?
-Capacity of 1100 gallons
- Has overflow and drain lines to storage tank
- Design Requirement 60 minute supply with 10% margin
-Transfer pump auto refills when Day Tank reach 731 gallons
-DG uses 6.4gpm at full rated load, able to supply 1.9hrs of operations at low level
Describe features of Fuel Injection Pump ?
-Positive displacement plunger type
-Driven by love on camshaft for timing of fuel delivery
-Has a fixed stroke and variable flow
-Variable flow is controlled by fuel control rack
-Cooled by Fuel Oil being pumped
Describe features of Fuel Injector ?
Atomizes the fuel going into cylinder for efficient combustion
What is the Fuel Rack for ?
Fuel Rack is a series of linkages,joints, and fuel control cylinder that connects Main Governor to fuel injection pumps
How does Fuel Control Cylinders work ?
-Uses control air and spring pressure to position Fuel Rack to either Min. Fuel or Max. Fuel
What position is fuel rack in when shutting down or standby ?
It’s in Minimum position due to control air vented from spring side
When does Fuel Rack go into Maximum Position ?
-On DG start signal control air is aligned to spring side causing cylinder to collapse, which positions it to Max. position
-Stays in Max. Position until 600rpm, then Main Governor takes over fuel control
Where is Main Governor located ?
Mounted on the aft end of engine driven by sprocket connected to camshaft
What is Main Governor used for ?
Maintains DG speed(600rpm & 60HZ) during various loading by positioning fuel rack which controls amount of fuel to Fuel Injection Pumps
How is Main Governor cooled ?
Has self-contained internal oil system with constant oil flow for hydraulic control, which is cooled by jacket water system
What happens if Main Governor electric speed control fails ?
-Backup hydraulic feature for speed control of engine
-Manual speed control,percent load,and droop adjustment
What is the differences in the hydraulic speed control, then the electric speed control ?
-Hydraulic portion isochronous with speed control,percent load,and droop adjustment
-Response to load changes are slower -Frequency is kept HIGHER @608rpm(60.8HZ)
Where is overspeed Governor located on engine ?
At the aft of the engine and driven from sprocket on camshaft
What is the Governor overspeed used for ?
-It provides overspeed protection by stoping air and fuel going to engine
When will the overspeed Governor protection actuate ?
-Will actuate at 660 RPM
-Trips closed turbocharger butterfly valves
-Aligns control air to Fuel Oil Cylinder causing full extension and stop fuel flow
What system lubricates the Overspeed Governor ?
The DG oil system and has self-contained hydraulic power source
What’re the tech specs for diesel fuel oil transfer ?
-Quality supply for 7 days
-Have greater than or equal to 80%INDICATED level in fuel storage tank
-Stored fuel oil must be less than or equal to particulate limit
- Must be appropriate grade and not contaminated so it doesn’t affect engine combustion
What is the purpose for having the Jacket Water system ?
It removes heat generated during compression and combustion process
When the engine is operating, what components is jacket water cooling ?
-Engine cylinder jackets
-Main Governor Oil
-Turbocharger
-Intake intercooler
When the Engine is not running what components is jacket water keeping warm ?
-Cylinder Jackets
-Intercooler heater core
-Main Governor Oil
-Turbocharger
What is maintaining the warmth in the jacket water system when the engine isn’t running ?
-A motor driven Jacket Water Circ. Pump & Jacket Water Circ. Heater
-They both cycle on and off at same time to maintain engine cylinder jacket Temp.
What happens if Engine Intake manifold gets to cold when in standby? Where does water go when done being used ?
-Sends some warm jacket water through the Intercooler Heater Core
-It goes back to Jacket Water Standpipe
When engine is running what components is Jacket Water cooling ?
-Governor Oil Cooler
-Cylinder Jackets
-Turbocharger
What is used to circulate Jacket Water when diesel is running ?
-Engine Driven Jacket Water Circ. Pump
- Jacket Water Cooler
When does the Jacket Water cooler need to be used when engine is running ?
-It is used when pump outlet temp. is to high, a percentage of water will be sent through cooler that is cooled by spray ponds
-If temp. Isn’t hot coming out of pump then the cooler will be bypassed
What level is the Jacket Water Standpipe maintained at ?
Maintained between 10-14inches in sight glass, with chemically treated water
What’re the 3 makeup waters sources ?
-Normal makeup is Demon. Water (DW)
-Backup makeup is Condensate Transfer & storage (CT)
-If both normal/ backup aren’t available a hose connect for Fire Protection(FP)
What’re the pumps powered by for the Demon. Water and Condensate Transfer & storage (CT) ?
-Demon. Water powered by non-class 480 MCC(NH)
-Condensate Transfer & storage powered by Class 480 MCC (PH) for emergency use
When will the Motor Driven Jacket Water Circ. Pump & Circulation heater turn on & off ?
Both pump and heater will energize at 120 Fahrenheit and de-energize at 135Fahrenheit
When will the Motor Driven Jacket Water Circ. Pump send water through Intercooler Heater, when engine isn’t running ?
When Air Intake Manifold temp. reaches <105 degrees Fahrenheit it’ll send warm jacket water through intercooler heater to raise above 105
When is the Jacket Water Cooler & TCV not in service ? What protection does Jacket Water heater have on low level ?
-They’re not in service when DG is in standby
-There is no protection for low jacket water level
What’re the Jacket Water Motor Driven Pump and Heater powered from ?
CLASS 480 MCC (PH)
What is the Engine Driven Jacket Water Pump connected to ?
-It’s chain driven from the crankshaft on forward of engine
What is the flow path for the Engine Driven Jacket Water Pump when engine is running ?
1.)Pump takes water from Jacket Water Standpipe
2.)Discharge of pump is sent to Temp. Control Valve
3.) Through Jacket Water Cooler
What is Temperature Control Valve used for in Jacket Water system ?
It is used to directed flow through the cooler or used to bypass the cooler based on Temp. discharge of Engine Driven Pump
What’re the Temp. Setpoint for the TCV flow direction on the Jacket Water System ?
Temp. In Degrees Fahrenheit:
-If temp is 175 or greater, ALL flow through cooler
-If temp is 165 or less, ALL water bypasses cooler
- If Temp is between 165-175, flow is directed through AND around cooler to maintain 170 degrees
What type of cooler is the Jacket Water Cooler ?
Shell & Tube Heat Exchanger:
-Jacket water through shell
-Essential spray pond through tubes
Where is the crankcase located ?
It is located on bottom of Engine Cylinder Block it encloses rotating crankshaft and crankshaft counterweights
What is the purpose for the CrankCase ?
Provides suction to oil pumps and stores sufficient oil for 7days of full load DG operation
What is used to maintain proper viscosity of the oil in the CrankCase to be able to start DG in 10 seconds ?
A Crankcase lube oil heater cycles on/off to maintain oil temp between 120-135 degrees Fahrenheit
What is used to circulate oil to pre-lubricate DG components ?
-A Motor Driven Pre-Lube Warm up Pump circulates oil through a Lube Oil Circulation Heater, to maintain oil temp. Between 120-135 degrees Fahrenheit
What is the discharge oil pressure on the Motor Driven Lube Oil pump ? What happens when 280rpm is met ?
-Discharge oil pressure is 50pisg when less than 280rpm
-Motor Driven Lube Oil pump turns off when 280rpm is reached
-Engine Driven Lube Oil pump take over at 280rpm
What must be running in order to have the Crankcase Lube Oil heaters & Lube Oil Circ. Heaters energized ?
-The Motor Driven Lube Oil Pre-Warmup pump need to be running in order to have heaters energized
-The both heaters are interlocked with the operator of the Motor Driven Oil pump
What system powers the Motor driven Pre-Lube Warmup Pump, Lube Oil Circ. Heater, and Crankcase Lube Oil Heater?
Powered from CLASS 480VAC MCC(PH)
What is the Lube Oil Cooler & Temperature Control Valve for?
-Lube Oil Cooler has oil pass through shell side & spray pond water through tubes
- TCV is to control oil Inlet Temp. To engine at 165 degrees Fahrenheit
What’re the TCV set points in the Lube Oil System ?
-Oil entering TCV less than or equal to 160 degree Fahrenheit bypasses the cooler
-Oil entering TCV greater than or equal to 170 degrees Fahrenheit is directed through cooler
- As oil reaches operating temp the valve will modulate to pass flow through cooler and around it to maintain 165degrees Fahrenheit
What’re the Lube Oil filters micron?
15 Micron filters to clean out oil prior to reaching engine components
What’re important details about the duplex strainers that’s after the oil filter in the Lube Oil System ?
-The strainers are 90 microns to prevent slag,rust,pipe scale,or ruptured filter
-Duplex strainers are normally both in service at same time
What is the 3-way valve for on the inlet and outlet of the duplex filter for the Turbo Lube Oil ?
It will reposition flow from filter(dirty) to other filter(clean), if one side of the duplex filter oil pressure fails below 33psig.
What’re the Turbo Bearing Oil Pressure Control Valve(PCV) used for ?
Pressure Control Valve limits oil pressure to Turbocharger to 35psig
What’re the Tech. Specs. for Lube Oil System ?
-Lube Oil greater than or equal to 2.5in in Diesel Crankcase sight glass(ensure supply for 7 day operation at full load)
What is the LCO for the amount of oil that is supposed to be in Crankcase ?
- Entering LCO is when oil level drops between 1in - 0.5in, need to restore level above 1inch in a certain amount of time
- If Crankcase sight glass level drops BELOW 0.5in, then that DG is declared inoperable
What does the Diesel Generator Building(HD) HVAC ESF ventilation system provide ?
Suitable Thermal environment & Ventilation:
-For operation of the Generator & its Auxiliaries, and for its electrical system during Testing and Emerg.
-For maintenance personnel during normal plant operation or normal testing of DG
- Ventilation of DG Fuel Oil Day Tank room to prevent accumulation of combustible vapors
The DG building HVAC system (HD) consists of following AHU,fans,and heaters ?
-DG control room Norm. Exhaust fan
-DG control room Essen. Exhaust fan
-DG control room Norm. AHU
-DG control room Essen. AHU
-DG air compressor Norm. Vent. Fan
-Diesel Fuel Oil Day Tank Vent. fans
-DG room Norm. Heaters
Building HVAC system maintains ambient conditions suitable for supplying ventilation, recirculation, and heating for what ?
-DG Room
-DG Control Room
-Diesel Fuel Oil Day Tank Room
-DG Air Compressor Room
-DG silencer room
What is Max. Temp of the DG Room and DG Control Room ? (per UFSAR)
Maximum:140 degrees Fahrenheit
Minimum:50 degrees Fahrenheit
When will the DG Control Room Normal AHU and DG Room Normal exhaust fan Auto-Start?
Will auto start when respective room temp is greater than 105degrees Fahrenheit to maintain DG room below 122 degrees F. When DG isn’t operating
When will DG room normal unit heaters turn on ?
-When room temp drops below 55degrees F.
-DG Normal Unit Heaters are fully auto once breakers are closed
When will DG Air Compressor Normal Ventilation Fan auto start?
-Auto start anytime an air compressor is running
-Or anytime temp reaches 100 degrees F. inside the DG air compressor room
How does the in-series Fuel Oil Day Tank Vent Fans work together ?
-One fan is normally running, while the second is in standby
-Second fan starts, if air flow from the running fan is to LOW
What’re the normal status of Building HVAC system (HD) ?
-DG control room Norm.AHU standby(or running based on temp)
-DG Room Norm.Exhaust fan standby(or running based on temp)
-DG control room Essen. AHU Standby
-DG room Essen. Exhaust fan Standby
-DG air compressor norm. Vent. Fan standby( or running based on temp)
- Fuel Oil Day tank Vent one fan running, second in standby(second fan runs if air flow to low )
-DG room norm. Heaters standby(energized based on temp)
What is the difference in the Building HVAC system(HD) between a running DG condition and a standby DG condition?
-Mostly the same except, the Essential AHU & Essential exhaust fans are running, while the normal AHU and exhaust fans are in standby
When does the Essential AHU& exhaust fans start ?
-They’ll start by a ESFAS load sequencer 25 seconds after DG reaches speed and voltage
-Will keep running until room cools less than 110 degrees
What essential component is slaved to the DG Room Essential exhaust fan ?
-The DG Control Room Essential AHU will start, when the Essential exhaust fan starts
-DG Control Room Essential AHU keeps DG Control Room cooled to less than or equal to 122degrees
What happens if DG Essential exhaust fans or DG Essential Control Room AHU aren’t available ?
The DG is declared inoperable
What is the Test Mode Shutdown method?
-Operator pushes “stop” push button locally or Control room turns switch to “stop”
-Cooldown cycle for 5mins which tests the two Emerg. Run solenoids and pneumatic trip circuits
What DG Normal Shutdown Sequence?
-Run relays de-energize and running loaded Light goes out
-DG output breaker receives trip signal
-Emerg. Run solenoids de-energize one at a time after 2.5mins(5 mins total)
-Engine stops after 5min cooldown
-Running idle light goes out
-Motor Driven Pre-Lube Warmup pump will START
With DG running in Test Mode what trip will immediately stop DG ?
Both Test Mode & Emergency Mode trips will immediately stop DG to protect it
What happens if DG receives Emerg. Start signal during the 5 min cooldown cycle ?
The cooldown cycle will stop and the DG will run in Emergency Mode
How can you manual stop the DG while it’s running in emergency mode ?
-The Emerg. Start signal (SIAS,AFAS,&LOP) that caused the DG to start is terminated
-DG is put in override, which is only possible from Main control room
What Emerg. Trips will immediately stop the DG when it’s running in Emerg. Mode?
-Overspeed shutdown
-Low Engine Oil Pressure shutdown
-Generator Differential
- Emergency Stop Pushbutton
-DG emergency shutdown sequence
What happens during an Overspeed shutdown trip of the DG ?
Sequence order:
-Overspeed DG will trip the Overspeed governor
-Then trips the Fuel Control Cylinder
-Which trips Intake Turbocharger Butterfly Valve
-This sequence stops fuel and air supply to engine
When an Overspeed Governor and Turbocharger Butterfly Valve trip, how do you reset them ?
They must manually be reset
Under what conditions will Low Engine Oil Pressure Shutdown initiate?
Two sets pressure switches in Engine Lube Oil Header:
-One set of switches stops engine in test mode from low oil pressure(Deactivates Test Mode trip solenoid)
-Other set of switches stops engine on low oil pressure in Emerg.Mode(Deenergizes Emerg. Mode fuel Control Solenoid Valves)
Why doesn’t the DG trip on low oil pressure when it’s just starting up ?
-The Pressure Switches are bypassed for 20 seconds during Startup/Shutdown when speed is <570rpm
When will a Generator Differential trip actuate ?
When there is difference in current from the inlet and outlet of the winding, which indicates the windings have fail
How does the system react during a Generator Differential trip ?
-Lockout relay on Local Generator panel trips,which de-energizes Emerg. Mode Fuel Control Solenoid Valves
-Lockout relay must be manually reset before DG can be restarted
What’re ways to manually stop DG if Emergency mode trips do NOT stop the DG ?
-Press DG emergency stop pushbutton
-Trip DG using Overspeed Governor
-Close Fuel Oil Day Tank outlet valve(cuts off fuel)
-Use Manual Fuel Rack Shutoff Lever to isolate fuel oil from DG
What is the Emergency Stop Pushbutton only purpose for ?
Used to Immediately stop DG for Emergencies only
How does PB interface with DG system ?
DG supplies power to PB bus during a LOP to affected Train
How does DG interface with PH system ?
PH provides power to (A/B Trains):
-DG control room Essential AHU
-DG Fuel Oil Transfer pumps
-DG Motor Driven Jacket Water Circ. Pump
-DG Jacket Water Circ. Heaters
-DG Motor Driven Pre-lube Warmup pumps
-DG LO Circ. & LO Crankcase Heaters
How does DG system interface PG system ?
PG provides power for DG Room Essential Exhaust Fans(A/B Train)
How does DG system interface with PK system ?
-PK provides power to DG low voltage panel for safety related interfaces to DG control cabinet
-PK provides DC power feed #2 for starting circuit and field flashing power
How does DG system interface with NH system ?
NH provides power to:
-DG HVAC control panels
-DG Control Room Norm. AHU’s
-DG Room Norm. Exhaust Fans
-DG Room Heaters
-DG Air Compressor Room Vent. Fans
-DG Fuel Oil Day Tank Vent. Fans
-DG Air Dryers
-DG Air Compressors
How does DG system interface with NK system ?
-NK provides power to low voltage panel for non safety related interfaces to non-class portions of DG control cabinet
-NK provides alarms, & instrumentation,such as Relays,
Meters, and Transducers for protection during testing
How does DG interface with Condensate Transfer & Storage system(CT) ?
Provides makeup water to Jacket Water Standpipe when Demineralized Water(DW) isn’t available
How does DG interface with Diesel Fuel Oil and Transfer(DF) system ?
DF provides onsite storage of fuel for at least 7days of continuous operations of DG at full load
How does DG interface with DW system ?
DW is normal source of makeup water to the Jacket Water Standpipe
How does DG interface with Fire protection (FP) system ?
-Last resort of makeup water to Jacket Water Standpipe if DW & CT pumps are lost
-FP connect to nearest fire hose connection
-FP provides pre-action sprinkler system for each compartment of DG building
How does DG interface with Essential Spray Ponds (SP) system?
-SP Provides cooling for DG Jacket Water and DG Lube Oil subsystems
-SP Cools sections of of the intercoolers
What is the time frame that the DG has to be secured within, if SP isn’t available?
-15 minutes unloaded
-2.6 minutes loaded
How does DG interface with Instrumentation & Control ( BOP ESFAS Sequencer(SA) system ?
DG Start Signal contact in the BOP ESFAS sequencer originated from BOP ESFAS DGSS module
When will the DG Start Signal contact close to start DG in Emerg. Mode or Test Mode?
-Loss Of Power(LOP)
-Auxiliary Feedwater Actuation Signal(AFAS)
-Safety Injection Actuation Signal(SIAS)
Starts in Test Mode:
-Containment Spray Actuation Signal(CSAS)
How will sequencing of DG work if the sequencer is lost ?
Manual sequencing would be required
How does loss of CLASS Control Power(PK) system affect DG system ?
1.)Engine will trip
2.)A loss of tripping capability of DG output breaker
3.)DG will not be able to start in Emerg. Mode or Test Mode
How does loss of NON-class control power(NK) affect the DG system ?
-Several alarms in main control room
-If running in Emerg. Mode it will continue running
-Will still auto start or start by use of simulated ESFAS&LOP push buttons on local control panel
-Main control room will not be able to start DG from board B01
How does losing control air, affect Emerg. Mode and Test Mode tripping devices ?
How would you trip the DG if control air isn’t available ?
You would have to manually trip DG by pulling lever to shut off fuel racks
Why would losing control air not affect Startup of DG ? Why does losing control air only affect shutting down of DG ?
-Standby position Fuel Control Cylinders are always at Max. Fuel position
-The Fuel Control Cylinder needs control air to shutoff fuel
What is the only automatic trip available when control air is lost ?
Only trip available would the Turbocharger Inlet Butterfly Valve tripped closed during overspeed
What happens when control air is lost when DG is running in Test Mode
All normal trips will start alarming and will trip the DG output breaker, BUT engine will continue running
What happens when control air is lost, when DG is running in Emerg. Mode ?
-Other emergency run trips like Low Oil Pressure & Generator Differential will ONLY trip DG output breaker,BUT engine will continue running
What’re the only ways available to shutdown the engine on loss of control air ?
-Manually trip the Turbocharger Butterfly Valve locally at the valve
What’re ways to shutoff the engine on loss of control air ?
1.)Manually trip turbocharger Butterfly Valve locally at valve
2.)Manually close valve for Fuel Oil Supply from Day Tank
3.)Hold manual fuel shutoff handle in off position until engine stops
4.)Take Main Governor Load Limit Control Knob to Min. Fuel position
What is the purpose of Integrated Safeguards (ISG) Testing ?
-Verify proper response of Class Emergency Diesel Generators & Engineered Safety Features(ESF) to simulated design basis events
How often does the BOP ESFAS system get tested?
At least every 18 months at time of refueling
What does testing of the BOP ESFAS system include ?
-Testing of sequence modes & ESFAS logic circuits
-Load sequencer timing
-Demonstrates operability of DG and safety related components
-Tests common mode failures on independent DG
-Partial verification of Safety Equipment Status(SESS) alarms
-Partial Verification of manual override functions for safety related pumps,valves,& fans
